A simple electrochemical strategy is reported for continuous monitoring of dynamic DNA methylation process over time. An electrochemical sensor was prepared by co-assembling of DNA probe and 6-mercapto-1-hexanol onto a gold electrode. The top of the DNA probe was labeled with 6-ferrocenylhexanethiol modified gold nanoparticle. The charge density between the C•G base pair was verified to be slightly reduced by DNA methylation, and could be further decelerated by ~ 25% upon co-locating a Br group onto methylated cytosine (mC). Therefore, in the presence of NaIO₄/LiBr, the progressively methylated DNA on the sensor showed a clearly decreasing current over methylation time. The dynamic DNA methylation process was indicated continuously from the current decrease ratio, with a limit of detection of 0.0372 µM. The strategy is convenient, cost-effective, and enable continuous profiling methylation process without distortion. Besides, the strategy was successfully applied for the studies on inhibitor screening and flanking sequence preference of DNA methyltransferase 3a. The results show that the activity of DNA methyltransferase 3a can be mildly inhibited by epigallocatechin gallate, and varies towards different flanking sequence with an order of 5′-CCGG-3′ < 5′-CGCG-3′ < 5′-CGCA-3′.

据报道，一种简单的电化学策略可用于随时间连续监测动态DNA甲基化过程。通过将DNA探针和6-巯基-1-己醇共组装到金电极上来制备电化学传感器。DNA探针的顶部用6-二茂铁基己硫醇修饰的金纳米颗粒标记。经验证，C•G碱基对之间的电荷密度会因DNA甲基化而略有降低，并且在将Br基团共同定位在甲基化胞嘧啶（mC）上时，电荷密度可能会进一步降低〜25％。因此，在存在NaIO ₄的情况下/ LiBr，传感器上逐渐甲基化的DNA在甲基化时间内显示出明显降低的电流。从电流降低率连续显示动态DNA甲基化过程，检测极限为0.0372 µM。该策略方便，具有成本效益，并且可以在不失真的情况下进行连续的甲基化过程分析。此外，该策略已成功应用于DNA甲基转移酶3a的抑制剂筛选和侧翼序列偏好性研究。结果表明，表没食子儿茶素没食子酸酯可轻度抑制DNA甲基转移酶3a的活性，并朝不同侧翼序列变化，顺序为5'-CCGG-3'<5'-CGCG-3'<5'-CGCA-3 ”。